How the parasitic worm has turned

Jun 14, 2010

(PhysOrg.com) -- Parasites in the gut such as whipworm have an essential role in developing a healthy immune system, University of Manchester scientists have found.

It has long been known that microbes in the gut help to develop a healthy immune system, hence the rise in popularity of probiotic yoghurts that encourage 'friendly' bacteria. But new research by Professors Richard Grencis and Ian Roberts shows that larger organisms such as parasitic worms are also essential in maintaining our bodily 'ecosystem'.

Professor Roberts, whose work is published in Science, explains: "It is like a three-legged stool - the microbes, worms and immune system regulate each other.

"The worms have been with us throughout our evolution and their presence, along with bacteria, in the ecosystem of the gut is important in the development of a functional immune system."

Professor Grencis adds: "If you look at the incidence of parasitic worm infection and compare it to the incidence of auto-immune disease and allergy, where the body's immune system over-reacts and causes damage, they have little overlap. Clean places in the West, where parasites are eradicated, see problems caused by overactive immune systems. In the developing world, there is more parasitic worm infection but less auto-immune and allergic problems.

"We are not suggesting that people deliberately infect themselves with parasitic worms but we are saying that these larger pathogens make things that help our immune system. We have evolved with both the bugs and the worms and there are consequences of that interaction, so they are important to the development of our immune system."

Whipworm, also known as Trichuris, is a very common type of parasitic worm and infects many species of animals including millions of humans. It has also been with us and animals throughout evolution. The parasites live in the large intestine, the very site containing the bulk of the intestinal bacteria.

Heavy infections of whipworm can cause bloody diarrhoea, with long-standing blood loss leading to iron-deficiency anaemia, and even rectal prolapse. But light infections have relatively few symptoms.

Professors Grencis and Roberts and their team at Manchester's Faculty of Life Sciences investigated the establishment of Trichuris and found it is initiated by an interaction between gut bacteria and the parasite.

They further found that a broad range of gut bacteria were able to induce parasite hatching. In the case of Escherichia coli (E-coli), bacteria bound to specific sites on the egg and rapidly induce parasite hatching. With E-coli, hatching involved specific bacterial cell-surface structures known as fimbriae, which the bacteria normally use to attach to cells of the gut wall.

Importantly, the work also showed that the presence of worms and bacteria altered the immune responses in a way that is likely to protect ourselves, the bacteria and the worms.

Intestinal roundworm parasites are one of the most common types of infection worldwide, although in humans increased hygiene has reduced infection in many countries. High level infections by these parasites can cause disease, but the natural situation is the presence of relatively low levels of infection. The team's work suggests that in addition to bacterial microflora, the natural state of affairs of our intestines may well be the presence of larger organisms, the parasitic roundworms, and that complex and subtle interactions between these different types of organism have evolved to provide an efficient and beneficial ecosystem for all concerned.

Professor Roberts says: "The host uses its immune system to regulate the damage caused by the bacteria and the worms. If the pathogens are missing, the immune system may not give the right response."

Professor Grencis adds: "The gut and its inhabitants should be considered a complex ecosystem, not only involving bacteria but also parasites, not just sitting together but interacting."

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No he is not. While it might be beneficial for your immune system, it'll still be harmful to your gastrointestinal tract.This in contrast with commensal E.Coli which is necessary for a healthy metabolism.

The element responsible for the immune reaction to the parasites is what's important. If this correlation is accurate, we just need to find a way to introduce this element without the worms.

Result? Eventually a population with a much lower incidence of allergies.

Strange to think that such a large swath of us are so far removed from our natural habitat that such a correlation could be made, I wonder what else we're missing that we will never even realize the farther from nature we go.

Recently read an extremely interesting article on how parasitic worms were studied in patients with celiac disease, an auto immune disorder. I don't remember the actual numbers or the specific species, but after the study the patients did not want to "get wormed" since for the first time they had become symptom free.

Here it is here:http://en.wikiped..._therapy-Germans used to have little shelves inside their toilet bowls where one could inspect their poop for worms before consigning it to the oceans. Tell me you didnt need to know that?

If theyve been with us long enough for symbiosis to develop, why do we find the idea so offensive, even to the extent that we worm our dogs?

We are not suggesting that people deliberately infect themselves with parasitic worms

Actually tapeworms were eaten, as they can help to keep the slim body. ­Opera singer Maria Callas was rumored to have used a tapeworm to achieve a remarkable loss of weight in the mid 1950s. She did, in fact, lose more than 60 pounds over several months. She was also known to have contracted a tapeworm at some point in her life.

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